Author Topic: Strange Knocking/Pecking noise that is intermittent.  (Read 1335 times)

Offline rdhack

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Strange Knocking/Pecking noise that is intermittent.
« on: July 17, 2018, 09:43:30 AM »
1982 GMC K1500 4 x 4 350 with TH350 Transmission

Shew, Do not know where to start. Have a noise that I thought was a rod bearing near the back of the motor. Was going to pull it up on ramps this morning & drop the oilpan to see BUT the sound is gone now that everything is cool. I have had this noise on & off for about a month.

Yesterday I checked the torque converter bolts and 1 of the 3 was loose but the other 2 were tight so it is not that.

What am I missing? Could it be the transmission going out? Do rod bearings not have slack when cooled off?

I am at a loss and would appreciate any help or advice I could get. Thank you in advance.

Addenum: Could it be a valve issue?
« Last Edit: July 17, 2018, 09:46:08 AM by rdhack »

Offline bd

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Re: Strange Knocking/Pecking noise that is intermittent.
« Reply #1 on: July 17, 2018, 10:24:06 AM »
It's possible that the click resulted from the loose converter bolt; more so if the flexplate is cracked.  With the engine off, use a bright flashlight and peer up all around the flexplate.  Look for rust tracks and cracks across the face of the flexplate.  Take your time and look carefully.  Flexplate cracks generally develop sub-concentric with the crankshaft flange and can be difficult to see.  You may need to remove the three bolts clamping the torque converter to the flexplate and slide the torque converter all the way rearward, which should provide a 1" - 1.25" gap through which to view upward toward the center of the flexplate.  Use a flywheel spanner to rotate the ring gear a few degrees at a time as you inspect for cracks. 
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline rdhack

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Re: Strange Knocking/Pecking noise that is intermittent.
« Reply #2 on: July 17, 2018, 10:39:25 AM »
Yes I had determined that most probably its the flywheel cracked BUT Thank you for that info. It very well could be the flexplate SINCE at this moment it only make the noise in reverse and no noise any other time.  THANKS!

Offline rdhack

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Re: Strange Knocking/Pecking noise that is intermittent.
« Reply #3 on: July 17, 2018, 10:42:43 AM »
OH MY BAD A flywheel and a flexplate is virtually the same thing. IM a Novice in some things BUT very mechanical for a school teacher. :)